Implanted biomaterials are finding increasing use in both dental and orthopedic applications in an aging American population. To enhance the incorporation of materials into the body, it is important to elucidate the factors that influence successful tissue-biomaterial interactions. Of particular interest is the role of micron-scale surface topography in determining the success of biomaterials. The objective of this investigation is to examine the effects of novel surface topographies on an osteoblastic-like cell line in vitro. The hypothesis to be tested in this study states that precise topographical features can modulate the attachment, morphology, proliferation, differentiation, and protein production of HOS TE85 cells in vitro in a predictable manner. The hypothesis is to be addressed by the following specific aims: (1) Create a family of polystyrene substrates with controlled, engineered surface topographies fabricated by Micro-Electro-Mechanical Systems (MEMS) technology. (2) Examine modulation of attachment, cell morphology, proliferation, differentiation and protein production with engineered surface topographies. (3) Investigate the role of substrate chemistry and composition on cellular attachment, proliferation, and differentiation. Techniques to be utilized include maintaining bone cells in culture, solvent casting of polystyrene substrates, light and scanning electron microscopy, and immunohistochemistry.